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C. D. EHRET.

METHOD OF AND APPARATUS FOR CONTROLLING ELECTRICAL ENERGY.

APPLICATION FILED DEC. 25% 19!].

1,303,184. Patented May 6, 1919.

Z-SHEETSSHEET 1,

C. D. EHRET METHOD OF AND APPARATUS FOR CONTROLLING ELECTRiCAL ENERGY. APPLICATION FI'LED 020.29; 1911.

1,303,1 84. Patented May 6, 1919.

2 SHEETSSHEET 2- MAM/V Q lllllmllk CORNELIUS D. EHRET, 0F PHILADELPHIA, PENNSYLVANIA.

METHOD OF AND APPARATUS FOR CONTROLLING ELECTRICAL ENERGY.

Specification of Letters Patent.

Patented May 6, 1919.

Application filed December 29, 1917. Serial No. 209,445.

To all whom it may concern Be it known that I, CORNELIUS D. EHRET, a citizen of the United States, residing in the city and county of Philadelphia, State of Pennsylvania, have invented a new and useful Method of and Apparatus for Controlling Electrical Energy, of which the following is a specification.

My invention relates to a method of and apparatus for controlling electrical energ particularly for purposes of signaling, telephony, or telegraphy, either Where the energy is transmitted from one point to another in radiant form, or when transmitted over a wire or other circuit.

My invention resides in a method of and apparatus for controlling the production, amplification, or both production and amplification of electrical energy by thermionic or electronic action occurring in connection with an audion, pliotron, vapor electric apparatus, and the like.

In accordance with my invention, the electric energy controlled, amplified or produced by anaudion or similar device is controlled by changing or varying both the emission of electrons from an incandescent cathode and the flow of the electrons. This is effected by controlling the temperature of the electronemitting cathode and the potential of the grid or screen.

My invention resides in the method and apparatus of the character hereinafter described and claimed.

For an illustration of some of the various forms of apparatus embodying my invention and suitable for carrying out my method, reference is to be had to the accompanying drawings, in which:

Figure 1 is a diagrammatic view of means for controllin both the temperature of a cathode and t e potential of a grid in an audion or like amplifier.

Fig. 2 is a diagrammatic view of an oscillating audion or like device with an arrangement for controllin both the temperature of the cathode and t e potential of the grid.

Fig. 3 is a diagrammatic view of apparatus constituting a modification of that shown in F' 1.

Fig i is a diagrammatic view of a further modification. v 1

Fig. 5 is a diagrammatic view of an audion or like amplifier in which the cathode is comprised of a plurality of parts, the temperature of one of which is controlled sicarbon or other suitable material, the grid g,-

and the plate or anode to, all as well understood in the art. Between one terminal of the filament f and the plate or wing w are connected the source of current B, which may be a battery of suitable electr c-motiveforce, and the primary 3) of a transformer or repeating coil whose secondary s delivers energy to any circuit, such as a circuit comprising a wire or wires extending between the transmitting and receiving stations, or

the antenna or other radiating element or 7 structure of a wireless or radio communication system. a

One terminal of the filamen f connects also through the secondary s of a transformer or repeating coil whose primary is p to the. grid or screen 9. In this grid circuit may be connected 2. device I), which may be a condenser 01' a source of electro-motiveforce, such as a battery; when a battery is employed its negative terminal is preferably connected to the grid and its electro-motiveforce is such as to maintain the grid suitably negative with respect to the cathode f. In the grid circuit may be connected also a source S of fluctuating or alternating current, and in the case of telephony particularly a source of fluctuating or alternating current whose frequency is above the limits of audition.

For rendering the cathode or filament f incandescent, thereis provided a source of current, as the battery 0, the strength of whose current through the filament f may be adjusted by the variable resistance r for giving to the cathode f a suitable normal temperature. In series with the battery 0 and the filament f are connected also the aforementioned primary p and the signal 111g instrument of any suitable character, as

for example, a telephone transmitter or microphone m. In lieu of a microphone or telephone transmitter may be employed a telegra h key or any other suitable type of controliing device or signaling instrument. W'hen sound waves, particularly the sound waves of the voice, impinge upon the microphone m, it varies the resistance in the circuit of the cathode f and of the rimary 2, thereby varying the current in t at circuit in accordance with the sound waves. As a result, the temperature of the cathode or filament f and the potential of the grid 9 are both simultaneously varied in accordance with the sound waves, with the result that in the plate or wing circuit appears electrical energy of far greater amplitude similarly varying in accordance with sound waves, this energy being transmitted through the transformer p, s to the signaling or telephone circuit or to the antenna or other radiating structure of a radio system.

When the source S is present, and speech or sound waves are to be transmitted, the frequency of'the source S is above audition and there is accordingly normally a variation of the potential of the grid 9 at a frequency corresponding with the frequency of the source S, with reproduction in amplified form in the wing circuit of electrical energy of correspondingly high frequency. However, when sound waves strike the microphone m the amplitude of these high frequency oscillations is varied in accordance with the sound waves by the simultaneous effects of changes in temperature of the cathode f and the potential of the grid 9.

In Fig. 2 is shown a known form of oscillating audion or similar device in which the wing circuit includes in addition to the transformer primary p, the primary p of a transformer whose secondary s is connected through a variable condenser 03 across the grid circuit. In the win circuit are also connected one or morevaria le capacities or condensers C, C, whereby the frequency of oscillations roduced by the apparatus may be varied. ridged across the wing circuit is the battery B and the choke coil or inductance e. In the grid circuit, in addition to the transformer secondary 8 there may be employed a battery h of suitable'electromotive-force for normally maintaining the grid 9 suitably negative with respect to the cathode f. The terminalsof the filament f are connected through the adjustable resistance r to opposite sides of the microphone or other signaling instrument m. There may be also associated with the filament f the battery i and the adjustable resistance 0".

Normally the apparatus produces oscillations whose frequency is above the limits of audition, these oscillations normally being of substantially uniform amplitude, so that there is impressed upon the circuit or radiator supplied by the transformer secondary 8 high requency oscillations of uniform amplitude. However, when sound waves are uttered against the microphone m, both the potential of the grid 9 and the temperature of the cathode f are simultaneously varied and thereby vary the amplitude of the high frequency oscillations in accordance with sound waves.

In Fig. 3 the arrangement and operation is in general similar to that of Fig. 1. In this case, however, the terminals of the filament f are connected to either side of the battery 0 through the'adjustable resistance r.

In Fig. 4 the arrangement and operation are in general the same as in Figs. 1 and 3. Here, however, the microphone m and the battery 0 are connected in series with the primary 10 only. Inductively associated wlth the primary 2 is a further secondary winding 8 connected in series with the filament f, the battery j and the adjustable resistance 1' Here again the potential of the grid 9 and the temperature of the filament f are simultaneously variedby the microphone or other signaling instrument m.

In Fig. 5 there is shown an audion or similar amplifier, in general similar to those shown in Figs. 1, 3 and 4. Fig. 5, however, shows that the source S, if employed, may be connected in parallel with the transformer secondary 8 instead of in ,.;series therewith, as indicated in Figs. 1, 3, 4, 6 and 7. And it will be understood as to Figs. 1, 3, 4, 6 and? that the sources S therein shown,'if employed, may be connected in parallel to the transformer seconj lary s ig. 5 shows, however, a cathode structure comprising the two filaments f and f, the former being connected in circuit with the battery I: and the adjustable resistance o The filaments f and f are both connected at one terminal to the wing and grid circuits. The terminals of the filament f are connected in circuit with the adjustable resistance 1', the transformer primary p microphone m and the battery 0.

In this case the filament f is not substantially affected by the microphone m, and it is the temperature of the filament f that is varied by the micro hone m simultaneously with the variation of potential of the grid The filament f may be smaller than the fila-. ment 7", and its normal temperature may be equal to thenormal temperature of the filament f, or it may differ therefrom.

In Fig. 6 is shown an audion or similar amplifier with a double filament arrangement similar to that shown in Fig. 5. In this case the filament f is in circuit with the battery 70 and the adjustable resistance W, and the filament f is in series with the same battery and resistance with the second III microphone m in series with them. The microphone m and the battery 0 are connected in series only with the primary 10 The two microphones are disposed close to I f is in circuit with the battery k and the adjustable resistance 1'; the second filament f is in circuit with the battery is, adjustable resistance r and the secondary s of a transformer or repeating coil whose primary is 12' connected in series with the primary p battery 0 and microphone m. Here again the microphone simultaneously controls the potential of the grid 9, and the temperature of the filament f, the latter through the transformer p, s.

In Fig. 8 is shown an audion orsimilar amplifier having two grids and two wings or plates. In general this is a known construction in which the grids g and g are connected to opposite terminals of the secondary s and one terminal of the filament structure is connected to the middle of the secondary 8 And the wings to and w are connected to opposite terminals of the primary p, whose center is connected through the battery B with the same terminal of the filament structure, and the filament structure and control are similar to that in Fig. 5.

Actuation of the microphone m lowers the potential of one of the grids simultaneously with the rise of potential of the other, and simultaneously the temperature of the filament f is varied.

If desired the battery or condenser b may be inserted in the grid circuits;'and if desired there may be inserted in the grid circuits the source S of high frequency oscillations or alternating current, the frequency being above audition when speech or sound waves are to be transmitted.

It will be understood that the various filament structures and grid controls are interchangeable with each other in the various figures.

It will further be understood that instead of delivering directly into the transmission circuit or into the radiating antenna or structure, the secondaries 3 may deliver into intermediate audion or similar amplifying devices of any suitable number and power for producing any suitable amplification.

What I claim is:

1. The method of signaling which consists in producing electrical energy in a circuit including a space traversed by electrons, simultaneously varying in accordance with the signal to be sent the temperature of an electron-emitting body and the potential of a body in the path of the electrons to cumulatively vary electrical energy in said path.

2. The method waves electrically, which consists in producof transmitting sound mg current in a path including-space traversed by electrons, and varying in accordance with the sound waves the temperature of an electron-emitting body and the potent-ial of a body in the path of said electrons, and impressing the modulated energy upon a transmitting medium.

8. The method of signaling which consists lnproducing carrier waves in a path comprising a space traversed by electrons, and varying the amplitude of said waves by simultaneously varying from their normal values in accordance with the signal to be 'sent the temperature of an electron-emitting body and the potential in the electron path.

4. The method of transmitting sound waves electrically, which consists in producng high frequency oscillations in a path compr sin a space traversed by electrons, and simu taneously varying in accordance with sound waves the temperature of an electron-emitting body and the potential of a body disposed in the electron path, and im pressing the resultant modulated high frequency oscillations upon a transmitting me dium.

5. The combination with a circuit including a space traversed by electrons, of means for impressing electrical energy thereon, means determining normal magnitude of flow of said energy across said space, and means for independently controlling said energy comprising means for simultaneously controlling the temperature of an electronemitting body and the potential of a body disposed in the path of the electrons.

6. The combination with an electronic device comprising a heated cathode, a grid and an anode, of means determining the normal value of the cathode ten'iperature, and means for simultaneously varying from their normal values the temperature of said cathode and the potential of said grid.

7. Telephonic transmitting apparatus comprising a heated cathode, a grid and an anode, and telephonic transmitting means for simultaneously controlling the temperature of said cathode andthe potential of said rid. g 8. Telephonictra-nsmitting apparatus comprising a heated cathode, a grid and a wing, wing and grid circuits, a transformer whose secondary is in the grid circuit, and telephonic transmitting means in the primary circuit of said transformer for controlling the temperature of said cathode.

- 9. The combination with an electronic device comprising a heated cathode, a grid and an anode, grid and anode circuits, capacity of a body disposed and inductance in one of said circuits, a coupling between the grid and anode circuits whereby high frequency oscillations are produced in the anode circuit, means determining normal cathode temperature, and means for modulatingsaid oscillations comprising means for simultaneously varying from their normal values the temperature of said cathode and the potential of said grid.

10. Telephonic transmitting apparatus comprising an oscillating circuit includin an electronic device comprising a heate cathode, a grid and an anode, a telephone transmitter for simultaneously varying the temperature of said cathode and the potential of said grid, and means for impressing the modulated oscillations upon a transmitting medium.

11. The combination with a heated cathode and an electrode spaced therefrom, of means for determining normal temperature of said cathode, and means for simultaneously varying from their normal values the potential of said electrode and the temperature of said cathode.

12. The combination with a heated cathode and an electrode spaced therefrom, of telephonic transmitting means for simultaneously varying the potential of said electrode and the temperature of said cathode.

13. The combination with a heated cathode and an electrode spaced therefrom, a transformer whose secondary is connected to said electrode, and means in the primary circuit of said transformer for simultanev ously controlling the current strength therein and the temperature of said cathode.

14. The combination with a heated cathode and an electrode spaced therefrom, a transformer. whose secondary is connected to said electrode, and telephonic transmitting means in the primary circuit of said transformer for snnultaneously: controlling the current strength therein and the temperature of said cathode.

15. The method of signaling which consists in establishin in a current path an electron emission 0 normal magnitude, and simultaneously changing from their normal magnitudes in accordance with the signal to be sent the potential of a body in the electron stream and the electron emimion.

16. The method of signaling which consists in changin in accordance with the signal to be sent t e conductivity of a current path by changin the number of electrons emittedby an eectron-emitting body, and simultaneously changing the capacity for electron flow of the electron path.

17 The method of signaling which consists in changing simultaneously and cumulatively in accordance with the signal to be sent an electron stream and the number of electrons supplied thereto by an electron emitting body.

18. The method of transmitting sound waves electrically, which consists in simultaneously varying in accordance with the sound waves the capacity for electron flow of an electron path and the number of electrons emitted by an electron emitting body, and impressing upon a transmitting medium electric energy modulated in accordance with the resultant electron stream.

19.- The method of transmitting sound waves electrically, which consists in simultaneously varying in accordance with the sound waves the capacity of a space fo electron flow and the temperature of a heated cathode, and impressing upon a transmitting medium electric energy modulated by the resultant electron stream.

20. The method of transmitting sound waves electrically, which consists in varying simultaneously in accordance with the sound waves the capacity of a space for electron flow and the number of electrons emitted by an electron emitting body, and impressing upon a transmitting medium oscillations having a frequency above aud'ibility modulated in accordance with the resultant electron stream.

21. The combination with an electronic device comprising a hot cathode and a grid controlling the electron stream, of means for adjusting the normal temperature of said cathode, and means for simultaneously varying from their normal values the temperature ofgaid cathode and the potential of said gr1 22. The combination with an electronic device comprising a hot cathode and a grid controlling the electron stream, of means for adjusting the normal temperature of said cathode, and signaling means for simultane ously varying from their normal values the temperature of said cathode and the potential of said grid.

23. Signaling apparatus comprising the combination with an electronic device having an emitter of electrons and a member controlling the electron stream, of means determining the number of electrons normally emitted, and means for simultaneously varying from their normal values in accordance with the signal to be sent the number of electrons emitted and the degree of control of the electron stream by said member.

24. Apparatus for electrical transmission of sound waves comprisin an electronic device having an emitter o electrons and a member controlling the electron stream, and means for simultaneously modulating in accordance with. the sound Waves the number of electrons emitted and the degree of control of the electron stream by said member.

25. Apparatus for electrical transmission of sound waves comprising an electronic device and an oscillating circuit for producing oscillations of frequency above audibility, said device having" an emitter of electrons and a member controlling the electron stream, and means for controlling said oscillations comprising means simultaneously modulating in accordance with the HOlllHl waves to be transmitted the number of electrons emitted and the degree of control of the electron stream by said member.

26. The combination with an electronic device comprising an emitter of electrons and a member controlling the electron stream, of means normally holding said member at a potential more negative than all parts of said emitter, and means for Si multaneouslyy varying the potential of said member and the number of electrons emitted.

27. The combination with an electronic device having a hot cathode, a plate and a grid, of means for normally holding said grid at a potential more negative than the most, negative potential of said cathode, and means for controlling the current through said plate comprising means for simultaneously varying the potential of said grid and the temperature of said cathode.

In testimony whereof I have hereunto aflixed my signature this 24th day of December, 1917.

CORNELIUS D. EHRET. 

